2.1 Gene Structure and Protein Synthesis Quiz

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Questions and Answers

What is the primary function of genes within the context of cellular activity?

To facilitate the transport of molecules across the cell membrane.

To control the synthesis of proteins. (correct)

To directly produce energy for cellular processes.

To directly regulate cell division.

Which of the following is a correct base pairing in DNA?

Guanine bonds with Cytosine (correct)

Adenine bonds with Guanine

Cytosine bonds with Thymine

Thymine bonds with Guanine

What constitutes a codon in the genetic code?

Three successive nucleotide bases. (correct)

Four successive nucleotide bases.

A single nucleotide base.

Two successive nucleotide bases.

What is the role of RNA in protein synthesis?

To carry the genetic code from DNA to the ribosome. (C) Signup and view all the answers

Where does transcription occur within the cell?

In the nucleus. (A) Signup and view all the answers

Which cellular structure is responsible for the actual assembly of proteins from the messenger RNA template?

The ribosome. (A) Signup and view all the answers

What are the building blocks of Deoxyribonucleic acid?

Phosphoric acid, deoxyribose, and nitrogenous bases (D) Signup and view all the answers

Where are ribosomal proteins formed?

In cytoplasm of the cell (D) Signup and view all the answers

What is the primary function of ribosomes attached to the rough endoplasmic reticulum?

Producing proteins that enter the reticulum matrix (D) Signup and view all the answers

Which of the following is NOT a direct function of protein enzymes produced in cells?

Regulating the transcription process in the nucleus (B) Signup and view all the answers

What is a defining characteristic of enzyme regulation?

It relies on negative feedback to control substance synthesis (C) Signup and view all the answers

What is the primary function of genetic regulation?

To manage the quantities and proportions of cellular components (C) Signup and view all the answers

How does the cell cycle of a rapidly reproducing cell typically end?

Through mitosis, cell division into two daughter cells (A) Signup and view all the answers

What does 'semi-conservative' describe in the context of DNA replication?

The method of replication where half of each new DNA molecule comes from the original DNA (C) Signup and view all the answers

What is the role of 'proofreading' in DNA replication?

To correct any defective areas of the DNA molecule (C) Signup and view all the answers

How does cell size directly relate to the nucleus?

The amount of functional DNA in the nucleus determines the cell size (D) Signup and view all the answers

What is selective repression of gene promoters responsible for in regards of development?

The differentiation process that leads to different cell types (C) Signup and view all the answers

What is the key distinction between apoptosis and necrosis?

Apoptosis is a planned cell death, while necrosis results from cell injury (C) Signup and view all the answers

What normally prevents tissues from shrinking or growing excessively?

Controlled balance between programmed cell death and new cell formation (A) Signup and view all the answers

What is the PRIMARY cause of cancer at the cellular level?

Uncontrolled cell mutation and abnormal activation of cellular growth (B) Signup and view all the answers

Why do most mutated cells not lead to cancer?

Mutated cells often have decreased survivability and normal feedback controls in place. (D) Signup and view all the answers

What is a typical immune system response to mutated cells?

The immune system recognizes and destroys most cells that have abnormal proteins. (B) Signup and view all the answers

What is the role of hormones in cellular function?

Control intracellular biochemical reactions by activating or inhibiting control systems (D) Signup and view all the answers

What factor must be present simultaneously for cancer to develop according to the content?

At least two genes, one for rapid reproduction and one for blood vessel formation (D) Signup and view all the answers

Which of the following is identified as the most significant carcinogen leading to cancer deaths?

Cigarette smoke (C) Signup and view all the answers

How does ionizing radiation contribute to cancer development?

It ruptures DNA strands, causing mutations (B) Signup and view all the answers

What is a characteristic behavior of cancer cells compared to normal cells?

They proliferate indefinitely and consume nutrients (D) Signup and view all the answers

Which of the following factors can increase the probability of mutations leading to cancer?

Exposure to certain chemical, physical, and biological factors (A) Signup and view all the answers

What role do oncoviruses like hepatitis B and C play in cancer development?

They increase the risk of developing cancer (D) Signup and view all the answers

What effect can cancer cells have on vital organ function?

They can replace normal tissue, hindering organ function (B) Signup and view all the answers

What is the relationship between cancer cells and blood vessel growth?

Cancer cells can produce angiogenic factors to stimulate new blood vessels (D) Signup and view all the answers

Study Notes

Gene Structure and Function

Genes influence all aspects of body structure and function
Genes are composed of DNA, a long double helix molecule
DNA building blocks: phosphoric acid, deoxyribose, and nitrogenous bases (adenine, guanine, thymine, cytosine)
DNA backbone: alternating phosphoric acid and deoxyribose molecules
Nitrogenous bases pair: adenine with thymine, guanine with cytosine
Genetic code: successive triplet bases (three bases = one code word)
Triplet bases control amino acid sequence in proteins

Protein Synthesis

Transcription: DNA code transferred to RNA in the nucleus
- RNA diffuses from nucleus to cytoplasm
- DNA stays in nucleus
- Multiple RNA types exist (messenger, transfer, ribosomal) with varied functions
  - Ribosomes are formed in cytoplasm, not nucleus
Translation: Protein formation in ribosomes
- Ribosomes read messenger RNA, producing protein chains
- Single mRNA can be read by multiple ribosomes simultaneously
- Rough endoplasmic reticulum (ER) involved in protein synthesis and transport

Gene Regulation

Genetic regulation controls protein synthesis from transcription to protein formation
Different cells express different genes despite shared genetic code (e.g., cardiac vs. epithelial cells)
Enzyme regulation: Control mechanisms to regulate enzyme activity
- Activator or inhibitor substances (e.g., hormones) can increase/decrease enzyme activity
Two Principal Mechanisms:
- Genetic regulation (activating/inhibiting genes)
- Enzyme regulation (activating/inhibiting enzymes)

Cell Reproduction

Genes control cell growth and division (mitosis)
Cell life cycles vary (10-30 hours for some cells; lifetime for others; Bone marrow cells, smooth muscle cells, neurons)
Cell Replication (DNA): DNA replicates into two identical strands (semi-conservative method)
Proofreading & Mutation: Enzymes correct replication errors; mutations result from undetected errors

Cell Death and Cancer

Apoptosis: Programmed cell death; cells shrink, condense, and are then digested.
- Contrast with necrosis (cell swelling and bursting)
Cancer: Caused by mutations (among other factors) in cellular genes that regulate growth & mitosis
- Most mutated cells die
- Cancer develops when mutated cells evade normal feedback controls, evade immune system, or develop angiogenic factors

Cancer Development Factors

Mutations in multiple genes required for cancer development
Environmental factors (e.g., radiation, chemical exposure) increase mutation chances.
Hereditary tendencies reduce the number of required mutations by inheriting pre-cancerous genes
Viruses (e.g., hepatitis B, C, HIV) can increase the risk of cancer
Invasive characteristics: Cancer cells tend to detach, move, and metastasize.
Competition for nutrients, disruption of organ function

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Description

Test your knowledge on gene structure, function, and the processes of protein synthesis. This quiz covers topics such as DNA composition, transcription, and translation mechanisms, important for understanding biological functions. Assess your understanding of how genetic codes influence protein formation.